


You're Growing on Me

by ferric



Category: Shingeki no Kyojin | Attack on Titan
Genre: Biology, Chemistry, M/M, probably?, some science thingy, teehee there are puns, very brief mention of science
Language: English
Status: Completed
Published: 2014-08-13
Updated: 2014-08-13
Packaged: 2018-02-13 01:52:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 8,233
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2132709
Author URL: https://archiveofourown.org/users/ferric/pseuds/ferric
Summary: <blockquote class="userstuff">
              <p>It is a truth universally acknowledged that a grad student in possession of unwanted lab work must be in want of an undergrad slave. AU where Eren is a premed student.</p>
            </blockquote>





	You're Growing on Me

**Author's Note:**

> For [nikooki](http://nikooki.tumblr.com/) because she once expressed a need to see premed Eren, and since she is so awesome and deserving of all the nice things in the world, I want to write something like that for her. \O/
> 
> I was inspired by her FRET (Förster resonance energy transfer) [post here](http://nikooki.tumblr.com/post/86574512618/dont-look-at-me-im-a-huge-science-nerd) , so I tried to find a recent paper involving FRET. To be honest if anyone is curious they should ask nikooki about FRET because I still have no idea. 
> 
> Disclaimer: Despite researching into a lot of things, I know very little about biochemistry and as a result a lot of things here might be inaccurate. References are placed at the end of this fic, if anyone is interested.

 

 

 

On Monday Levi came into lab early, opened the door, looked inside, promptly shut the door, and walked straight to Erwin’s pretentiously large office at the other end of the hallway.

“Erwin,” Levi said as he walked into the office. Erwin looked like he hadn’t slept in days, hunching over a brunch of drafts for a grant proposal that NIH would reject for not curing cancer and project requests for access to the ALS that Nile would reject on principle because Nile was a dick. It made sense to Levi then why he saw what he saw in the lab room.

Erwin looked up, and Levi would feel sympathy for the dark circles under his eyes had he not sported some of his own writing those proposals that Erwin promised to look over a month ago but ended up taking a vacation in Antarctica of all places.  For the two weeks that Levi was hypothetically chewing his nails waiting for Erwin, he had no sympathy for the man now. “Good morning, Levi.”

Levi had no time for nicety. “Why the hell did you put that thing in lab?”

Erwin frowned in confusion, and Levi remembered that Erwin, as a faculty here, never go into lab unless he was supervised by people who actually worked in lab, aka Levi and the other grad students and possibly the French post-doc who spent too much time being full of himself to actually do work.  As a result the atrocity in the lab room couldn’t possibly be his fault.

“What I put in lab,” Erwin murmured, probably racking his brain trying to remember that they had a wet lab, and Levi was about to leave him be and stormed to the other office to find out which grad student and/or post doc was to blame when Erwin perked up.

“Oh! I know,” He jerked from his seat, and the pencil perching behind his ear clattered to the ground. “Ah I was looking for that.”

Levi watched with little amusement as Erwin fumbled for the pencil, tapping his feet impatiently on the linoleum floor.

“That _thing_ ,” Erwin said as he triumphantly twirled the pencil on his fingers, giving Levi a disapproving look. “Is an undergrad student.”

“I know what that is,” Levi snapped. “I’m asking you why it was put there.”

“His name,” Erwin frowned. Apparently undergrads must not be referred to as inhuman even though they were. “Is Eren Yeager. He’s a very promising premed student—”

“Oh god helps me,” Levi moaned. He taught those before. He went into lab to avoid further contact with them, not to prolong it. “Please tell me he’s not a first year.”

“He’s a third year.”

“Thank god for small mercies,” Levi muttered. “Why the hell did you get an undergrad? We don’t have money to pay him. You don’t even have time to teach him. You don’t even have time to teach the class you’re supposed to be teaching now.”

“I’m glad you understand!” Erwin said excitedly, and because Levi’s survival instinct was like no other, he backed out of the room slowly. “Educating young scientists is exactly the goal we must pursue as a group.”

“I don’t understand,” Levi said, sensing correctly that Erwin was about to make him do something that he didn’t want to do, but he would still have to do it because he was under Erwin’s payroll. “I’ll just leave you to your work then.”

“So of course you can help me by working with Eren instead.” Erwin was undeterred, the bastard. “He’ll have a lot to learn from you.”

“No, it doesn’t. Ask Hanji instead. I’m sure he could grow cultures for her or something.”

“Hanji is on vacation,” Erwin said. Fuck, was everyone on vacation? Why wasn’t he on vacation? Clearly Levi had missed the memo somewhere along. “Besides, this is the perfect time to take in an undergrad. You don’t have to teach classes, and you’re just starting on a new project.”

Levi wanted to chuck something at Erwin’s face. Preferable something dirty. Preferably his shoes, but they were nice lab shoes and he had to get back to lab eventually. “This is exactly why it’s a bad time. If I don’t know what I’m doing myself, how can I teach that kid?”

“Teaching is the best way to learn.” Erwin nodded.

Levi glared.

“Besides, Eren is a very motivated student,” Erwin said with confidence of a man knowing that despite Levi’s protests, he had to do whatever Erwin told him to. “I think you’ll like him.”

Levi let out a heavy sigh through his nose. He highly doubted that they would get along. Levi had a history with premeds, ever since that nasty incident his first year when he refused to let one of them makes up a series of quizzes and labs because the kid missed sections for non-emergency family trips (Aspen did not constitute a family emergency). Needless to say he nearly got fired for it and made an enemy of the dean of the college after that.

The kid later went to the University of Washington’s School of Medicine. He once emailed Levi to gloat. Levi had kept his mouth shut and moved on because Dean Weiss made it very clear that the kid’s father, a generous donor to the university, must not be agitated.

The past was the past, but it still meant that students avoided getting Levi as an instructor if they could. It stung even though Levi didn’t like to teach. Luckily aside from that one incident, Levi’s experience with teaching improved dramatically, and he liked his students enough.

 

But the truth stood that Levi didn’t like teaching and he wasn’t any good at it, so ever since the premed-incident-that must-not-be-spoken-of-anymore happened, he vowed to never get an undergrad assistant, so matter how much Hanji claimed that they were fantastic.

“Levi,” Erwin said, all mirth gone. Levi straightened his shoulders in response. “If you take him, Dean Weiss will get off your back.”

Levi perked up at that. He had wanted access to the microscopy facility, but any off-campus spending must be approved by Dean Weiss, and he was still on the Dean’s blacklist. “Completely?”

“Completely. Your request to use the SEM will finally be pushed through.”

“That’s almost worth the amount of trouble of having an undergrad,” Levi said even though he silently thought that if he could have access to the SEM then he would be willing to take as many undergrads as Dean Weiss wanted him to. Not that he would. By that point it was much easier to ask Hanji to take samples up to the facility for him.

“I’m glad that we see eye to eye.” Erwin smiled. “Now, do you have five minutes because I am trying to decipher Auruo’s nearly incomprehensible report and you’re the only one who knows what he’s talking about.”

Five minutes turned into thirty minutes because they began discussing the revision for the grant proposal, and by the time he returned to the lab, Eren waited a good half hour for nothing.

“Hi,” Eren said when Levi walked in. “I’m Eren Yeager.”

“Levi,” Levi introduced himself. They shook hands. He glanced at the notebook and worksheet on Eren’s lap.

“Just reviewing for a class,” Eren said, closing the notebook and putting it back into his backpack. Levi noted with approval that Eren already found the box of safety glasses by the door and was already wearing one.

“So,” Levi said once he had Eren’s eager eyes back on him. “Erwin said you’re going to work under me. I’ve recently finished my teaching requirements so I didn’t have time to work on the project that I started in January.”

“So you have nothing for me to do?” Eren finished Levi’s train of thought. At least the kid caught on quickly. “I could help you start things if you send me some references to read.”

“I’ll send them to you after I give you a tour of the lab,” Levi said.

“Sounds great.”

They walked through the lab; Levi showing Eren all the equipment and explained how they worked while Eren listened attentively. More importantly, Levi directed Eren’s attention to the label on the side of the instruments indicating the person in charge of the instrument and their contact information.

“If you have any question, you can come ask anyone in the lab, not just me,” said Levi. “We all know how to use these instruments, and the person in charge of the instrument should only be contacted when something goes wrong.”

“Okay.” Eren nodded.

“More importantly.” Levi turned to Eren, stopping at the door once the tour was over. “You must ask for help if you have any problems in lab. No ifs and/or buts.”

Eren opened his mouth to say something then closed it. “Right.”

“That is the most important thing you have to remember. You don’t have to remember what I said about the equipment in this lab because I’ll train you on the ones you need.”

“Okay.”

“Good.”

“Also, no lab work unless I’m around.”

“Okay.”

Eren immediately began once he finished the safety trainings and read all the references that Levi gave him.

“I’m taking classes and volunteering at the medical school,” Eren explained when Levi asked about his schedule.

“Of course you are,” Levi muttered under his breath. This type always volunteered at hospitals. This type was also highly independent and determined to do thing by themselves.

Which was why Levi wasn’t surprised to find Eren in wet lab one afternoon, looking wide eyed at the electrophoresis gel and having no idea what to do.

“Let me show you how to use it again,” Levi said, and Eren looked guilty.

“Sorry.”

“Why are you apologizing?” Levi’s words came out sharper than he intended to if Eren’s wince was any indication. “Don’t apologize. Just learn.”

So Levi showed Eren how to run the gel again, and Eren tried it with him watching. It wasn’t difficult for Eren by any means, but the first time in lab had always been nerve wrecking for a lot of undergrads.

“You did well,” Levi said stiffly, uncomfortable with giving out compliments that he wasn’t ready for.

“You did show me every step. Twice,” Eren said, sounding sullen.

Levi sighed. “Listen, I did take on the job of being your mentor. I will teach you. I’m not good at teaching, but I’ll try. But you have to try to trust me and ask for my help, alright?”

“Alright,” Eren said softly. “Thank you.” He looked at Levi with wonder as if he didn’t expect Levi to say those things, and Levi was willing to bet that Eren thought he was going to have his head chopped off or something ridiculous.

“The difference between this lab and the instructional one with your fellow premeds is that we actually want you to learn and do well, understand?” Levi rolled his eyes as he said it, knowing perfectly well how premed courses were. He taught some himself.

“Right,” Eren said. “Thank you.” And then Eren’s gaze was too warm for comfort, so Levi turned away, babbling something about fixing his set up.

Eren was a hard worker for the limited time that he went into lab or at least, whenever Levi saw him. Levi was busy doing the laser set-up in the laser room, and Eren was busy doing cultures in the wet lab. He told Levi that he knew how to do dissections and cultures, but Levi went over them again with him anyway and supervised the first three times he tried both. After that, whenever Eren came into lab, he simply told Levi what he was going to do and leave to do it without supervision.

Levi had to grudgingly told Erwin later that having Eren around was great because now he had time to set up the laser, a task complicated by Erwin’s insistence that he had to share with Auruo, so now he had to make sure the set up could be modified for both projects.   

“He keeps forgetting to change the filter,” Levi complained to Eren one day while they were eating lunch in the break room. “And using the log book is beyond him. I don’t know how he got into grad school.”

Eren would nod sympathetically whenever Levi went on an angry rant about the laser, but it wasn’t until about three days after Levi became comfortable enough with Eren to use the kid as a make-shift therapist that Eren had the courage to ask. “What is a filter?”

Levi stopped in his track because he completely forgot that Eren didn’t know any of this stuff, and Eren, after he saw the expression on Levi’s face, hastily said, “I could look it up later.”

“No, I’ll just tell you. It’s my job to teach you,” Levi said, then realized that he had not done any teaching for Eren at all, but just made him do grunt work . He felt guilty. “A filter is a piece of optics. When the laser goes through, it rejects unwanted wavelengths and transmits wanted ones. I used a 657 nm long-pass filter, so I’m filtering out light that’s 657 nm to use.”

“Oh okay,” Eren said.

After thinking about it some more, Levi offered. “If you want, I can show you what’s in the laser lab?”

“That’ll be great.” Eren beamed, and Levi’s heart did the same. It had been awhile since he saw a student eager to learn like Eren. “Not that dissecting mice isn’t exciting, but it gets old after a while.”

Levi winced. “Someone has to do it though. We need neural cells, and they’re hard to come by.”

“I don’t completely understand what the cells are for.” Eren flushed at his admission, and Levi felt like shit for not explaining things to him properly.

He set his lunch aside and grabbed the notepad and the pen lying freely on the table. “Let’s start from the beginning. “What do you know about FRET?”

It turned out that Eren knew about FRET from a molecular biology class he took, and he apologized unnecessarily for his lack of knowledge beyond that. Levi waved it off, reminding Eren that people got their Ph.Ds for this stuff, so of course it was normal for him not to know. Levi drew pictures while he explained, from the basics of FRET to the fundamentals of imaging to a rough course in lasers, all the while Eren listened and interjected with questions along the way.

Luckily for Levi, Eren was a focused learner.

“So we want to image neural changes using FRET?” Eren asked, finally coming to a vague understanding of what was going on.

“Basically,” Levi said. He ripped out the pages of the notepad filled with various drawings and bullet points and handed them to Eren. “Here. Keep this if it helps you remember. Don’t feel bad if you forgot 90% of what I just told you.”

“Thank you.” Eren’s smile was a lot more genuine than the ones Levi had seen on his face before, the polite ones he gave everyone when he first came to this lab. “I only remember the parts at the end,” he admitted.

“You’re doing a lot better than that French post-doc we have then,” Levi said, and Eren laughed.

“You’re a lot different from what I’ve heard about you.” Eren slid the papers into a folder and put it in his backpack.

“What did you hear about me?” Levi asked even though he had a feeling what Eren had heard. He told himself that he didn’t regret the-premed-incident-that-must-not-be-mentioned-anymore, but sometimes, he wondered if he could have gone along with it to make his life easier.

“I heard you tried to crush a student’s chance at med school by intentionally failing him.”

“Close enough.” Levi nodded.

“What happened?”

“What? I thought you heard about it.” Levi’s lips twitched, but there was no humor in it. He didn’t regret what he did, but it didn’t mean he didn’t feel terrible about it.

Eren’s eyes softened, and Levi had a strange feeling that he was being comforted by him. “I want to hear what you have to say about it.”

Levi swallowed. The only person who asked him for his side of the story was Erwin. When the issue was brought up to the Dean, they did ask him to explain, but it didn’t matter what he said because the kid’s father was a generous donor, and he brought a lawyer with him. The university didn’t want a lawsuit. Levi had to apologize and pass the kid.

“I explicitly said that missing two labs meant the highest grade a student could get is a C. The student missed two labs plus a series of quizzes because it was his last semester before medical school. He missed the labs during his time in Aspen, and he missed the quizzes because he decided to skip section. He then missed a midterm. I failed him. He asked for make-ups the last two weeks of classes before finals. I said no.”

“He told me that this class didn’t matter to him because he had gotten into med school already. I told him then that it shouldn’t matter if I decided to fail him. His father and their lawyer came. The dean of the college took their side. I apologized. Rather than making up for the missing assignments, they demanded that I pass him. I did. But I didn’t give him higher than a C.”  

There was much more than that. The kid’s father threatened not only to sue the university but also Levi. Levi would never forget it, their smug faces across the conference table. The thought that this twenty-two year old child was going to medical school while other deserving kids couldn’t because he had money, all the while his father refused to let him grow up, it almost made Levi dare them to sue. But in the end, he wanted to keep his place at the university.

It was all in the past.

“I grew up not having a lot,” Levi admitted softly. “I also grew up thinking that if I work hard enough, I could be equal to the people who had more than me. But sometimes, hard work isn’t enough,” Levi finished.

He watched Eren warily, wondering what he was going to say.

“That C is more than he deserved,” Eren said. Levi was startled by the amount of fury in his eyes. It was understandable though. Eren was the hardest working student Levi had ever met. In minutes waiting for equipment to be done, Eren always had his textbook or notebook out, reviewing materials from his class. In fact, Levi didn’t think he knew anyone who was determined as him, and somewhere in his brain, he had to admit that Erwin was right. He did like Eren. It was difficult not to like him. “I thought the system is supposed to weed out premeds like this.”

“It happens. At least it didn’t affect the grades of the other ten people in the class since the class was on a curve,” Levi said. “Sometimes the system fails. All I could hope for is that it works for people who deserve it.” _Like you_ , Levi wanted to say but didn’t.

“It’s people like him that bad doctors could get out into the world.” Eren clenched his fists. He was much more passionate about this than Levi expected him to.

“Med school should weed them out,” Levi said in an attempt to console Eren, but that only fueled Eren’s fury further.

“It should, but it doesn’t.” Eren’s fists were clenched so tightly that the knuckles were turning white.

“Eren?”

Eren snapped up to meet his eyes. “Sorry,” he shook his head and turned away.

“It’s fine,” Levi said, knowing that there was more to this than Eren was willing to admit. It wasn’t his place to ask however, and if Eren wanted to tell him, he would.

The following week Levi showed Eren the laser set up, and Eren expressed a lot of interest in it even though he admitted he didn’t want to work on building it with Levi. Levi was fine with that. Spectroscopy wasn’t for Eren, and there was nothing wrong with it.

They ate lunch in the break room together on the days that Eren showed up to lab, and as midterm began to creep up, Eren began to study during his lunch break. One day, Levi took a peek at Eren’s notes and perked up. “Is that the spectroscopy on biological systems class taught by Mike?”

“Yes, it’s the class by Professor Zacharius,” Eren said. “The midterm is coming up, and I’m having a lot of problems with the mass spectrometry unit.”

“What do you have problems with specifically?” Levi asked. Spectrometry was Levi’s thing. Mass spec used to be his thing before he switched labs. He would have no problems explaining basic mass spec to Eren.

“I’m having problems with this spectrum.” Eren slid the paper to Levi. “Is it—” He paused, sounding hesitant. “Can I ask you for help?”

“Didn’t I say on the first day that asking for help when you don’t understand is a rule?”

“Yeah, but I didn’t think it extends to classes,” Eren mumbled.

“Now you know.”

Levi took a quick look at the spectrum and at the molecule Eren drew out. Within a second of scanning the fragmentation pattern, he noticed it right away. “These peaks here.” He flipped the paper back to Eren, tapping on the peaks he was referring to.

“I have no idea why they’re there.”

“This is what happens when you have chlorine or bromine in your organic compound. Do you have a paper?”

“You can write on the back of that spectrum.”

Levi drew out the fragmentation that caused those ions and proceed to explain to Eren why patterns with chlorine or bromine containing compounds might not be that straightforward. Eren nodded in understanding, and because he was more comfortable with asking Levi coursework questions, asked other questions that he had as well. Levi spent hours helping Eren review for his exam, and by the end of it Eren looked like he was going to collapse in relief.

“If I pass this class, it would be because of you,” Eren said.

“You’re the one who did all the work,” Levi mumbled, trying to hide the fact that his face was heating up.

Eren ended up passing the class with flying colors, and Levi was so happy for him that he organized a group lunch for it. The entire group was always up for an hour of free time outside of lab, so they all agreed readily.

“Besides, we never had the welcoming lunch for Eren,” Hanji said, who didn’t resurface from the laser lab after her vacation until the email for Eren’s lunch came up. “Pass the water please.”

They decided to go to a Pakistani place that everyone loved tucked in a street quite a distant walk from campus and thus mostly undergrad-free on a Thursday afternoon. It was a narrow place, squished between two larger stores, but the delicious smell and warmth wafted onto the street was enough to alert pedestrians of its presence. 

The group ended up connecting two tables to accommodate everyone. Levi was squished between Eren and the back wall.

Predictably, Levi got the Nihari. Everyone gave him a hard time for getting it again, but promptly after that two people ordered the same thing. Eren got the chicken Samosas and the Alo Palak, both of which Levi liked a lot. Eren had great taste.

“So Eren, how is Levi treating you?” Erwin asked. Everyone on the table looked at Eren with interest.

“I hope he’s not torturing you too badly,” Hanji smiled.

“Oh sush, I’m sure Levi was perfectly nice to him,” Petra said. “Right?” She turned to Eren.

Levi rolled his eyes as they talked about him. That was why they were having a conversation at a food place. At least he could ignore them and focus on the food.

“He’s great,” Eren said, and as much as Levi liked do pretend that he didn’t care, Eren’s words made him feel lightheaded. “He taught me everything I know about spectroscopy.”

Erwin laughed. “Well that’s the way to Levi’s heart. Mentions spectroscopy and you’ll be the best thing since slice bread.”

“Eren is great himself,” Levi interjected before Hanji could make a comment about Levi’s obsession with spectroscopy. Eren’s eyes jumped up to meet his in surprise. “He’s a quick and hard worker, and he’s probably the best premed I’ve ever met.”

“I’m the only premed you could stand,” Eren corrected, a grin stretching wide across his face. “One sample is not enough to draw a conclusion.”

Everyone laughed at that, Erd giving Eren a pat on the shoulder. “Good man, good man,” Erd said.

“Maybe I only need one,” Levi mumbled, and then Eren was giving him a strange look. Levi felt the tingle all the way to the tip of his fingers and toes.

Then Eren ducked his head, and Levi couldn’t see the expression on his face.

By the end of summer Levi got the laser set up completed, and Eren had mastered the art of doing cultures (well, more so than he did before). Levi found himself in wet lab often helping Eren with growing cultures even though Eren didn’t need the help because he needed cells for the experiment and because…well….

“I think you want to spend time with me,” Eren joked one day, although his eyes looked more hopeful than amused.

“I’m bored now that the laser set up is completed,” Levi said. It was partially true.

“I think.” Eren bumped his shoulder against Levi and lifted up the petri dish of neural cells that he should be more careful with. “I’m growing on you.”

“That is a terrible pun,” Levi scowled but couldn’t stop the smile that threatened to break over his face. Damn Eren. Damn him.

“I’ve never asked, but why did you decide to go to grad school anyway?” Eren asked, and when Levi gave him a look. “What?”

“Are you saying that I don’t look like the type?” Levi said.

“No, I’m just curious.”

Levi gave Eren one last suspicious look before returning his attention to the lab bench. “I was working as a bartender for a while, and one of the girls there was telling me about a beer brewing program here. Went through undergrad accumulating $30,000 worth of debt and a decision to do something else instead, and now I’m here.”

“This is a dramatic switch from beer brewing.” Eren gestured to the rest of the lab.

“It’s actually isn’t,” Levi said. “You’ll be surprised that how much chemistry is involved in beer brewing. I was interning at Three Sons’ as an undergrad working with processing and detecting defects in beer composition. Did a lot of spectroscopy while analyzing beer compositions, and then decided that I want to do more spectroscopy.”

“That’s interesting,” Eren said, and on anyone else it would have sounded sarcastic but Eren sounded like he meant it. “I can’t imagine it being easy with your debt though.”

“It’s not,” Levi sighed. “I’ll cross that bridge when I come to it.” He turned to Eren. “What about you? Why are you set on med school?”

Eren momentarily froze in his track, but he resumed easily. “The money’s good,” he said, his tone mocking, and Levi bit back a grin. “It’s the obvious answer, isn’t it?”

“Put that on your med school application and see what happens.”

“I don’t know. Sounds like a Harvard winning essay to me.”

Levi rolled his eyes.

Overtime, Levi realized that Eren had grown on him, as much as he didn’t want to admit it. Somehow Eren managed to charm his way into Levi’s heart, and Levi was too helpless to stop it. It made it difficult once fall came because Eren would be too busy with classes to stop by the lab. Eren promised that he could come once a week, but Levi waved it off, saying that he would rather Eren focused on his classes.

While Eren was off, Levi kept his attention on obtaining better fluorescent proteins for the FRET system. Mutations in the protein complicated the process, and Levi had to shuffle to other labs to ask for help because his biology was rusty. With his occupation with proteins, Eren’s absence didn’t feel as glaring as it had initially, although Levi always welcomed Eren’s return whenever he could make it. Eren asked him for help with classes often, and Levi had to convince him that it was nothing to feel guilty about.

By September, Eren approached him for help with his med school application.

“You’re graduating this year?” Levi asked incredulously. His time with Eren was shorter than he thought, and he felt a pang at that.

“This winter, actually,” Eren sounded apologetic.

“I’m just surprised,” Levi said. He thought he would have more time, but no.

“My scholarship is only enough if I graduate this December.”

Suddenly Eren cramming important classes in the summer made a lot more sense. Levi wished—but what would he do if he had more time with Eren? It wasn’t like—

“What do you need help with specifically?” Levi asked to squash away the train of thoughts that he didn’t think he should have.

“Could you look at my application essay?” Eren said. He gave Levi a sheet of paper, the word “Personal Statement” typed neatly on top. It looked awfully official for a draft and even had Eren’s name and date and contact information in the corner.

“Sure.”

“It’s a bit—” Eren hesitated. “Personal.”

“Well, that’s how a personal statement should be,” Levi said. Eren looked tense, and Levi had to ask. “Are you sure you want me to read it?”

Eren took a deep breath.

“I’m sure.”

Levi gave Eren one last searching look and began to read.

***

***

***

The death of his father, a medical doctor deployed to Afghanistan, was a silent pain that wafted through the house when Eren was growing up. He wasn’t old enough to remember his father, but the reminder was always there in the sympathetic voices of the people around him, talking about how brave his father was and how amazing he was for giving back in his sacrifice.

Eren didn’t think much about making sacrifices. He could never understand it, why his father was willing to leave behind his wife and a young son for a cause that people no longer believed in over time. In a way, Eren resented him for it.

His mother didn’t have health insurance. He did, through the state, but since his mother was young the state didn’t think it was necessary. If she could work, she had to fight for her health, was probably their reason. Wouldn’t want her to think she could get everything for free.

The cough and the fever came, but they weren’t worried about it at first since they had the flu before. Nevertheless his mother took him to the doctor’s, and with two painful weeks Eren got better. His mother was still sick, but she was older and anemic, both of which meant that the flu hit her harder and it would take her longer to recover.

It was a cold winter and they were waiting until the end of the month for his mother’s pay to hire a handyman to fix the heater, and Eren got nervous because his mother was getting worse. He would never forget it, the series of wet coughs that shook the house, her small body shivering under all the blankets Eren could pile on her while the small portable heater creaked by her bedside.  

 _Let’s go to the doctor’s, mom. Let’s go to the hospital. Let’s go_ , but they couldn’t afford it, besides, she had the flu before. It was fine.

Eren dragged her to a community clinic anyway, one of those small ones tucked in low-income neighborhoods. The bus sputtered and coughed along the way, and Eren kept his hand tight around his mother’s. She didn’t look any better even though the inside of the bus was warm. Her eyes were glassy, and it was like Eren wasn’t even there.

There was still a fifteen minute walk to the clinic, and Eren wanted to cry when his mother could barely keep herself up as they tread through the sidewalk, sinking into the snow that nearly went up to their knees.

The community clinic was a rickety old building that used to be a small construction company until it went out of business.  Eren counted the windows on the remaining smear of a building poster that was hastily ripped off, trying not to think about the overly crowded room and the sick people sitting in a yellowing white plastic chairs, coughing and sneezing and arms wrapped in bloodied bandages. He wished someone would free a seat, but there were only three doctors on staff, and the queue was so long. At least they could lean against the wall because his mother couldn’t stand without assistance.

Four hours.

It took four hours until someone saw his mother, and by then she was so out of it that she didn’t even respond to her name. Four hours and they could only take twenty minutes to look at her. Four hours and they had to go home, armed with just fever and cough medicine that his mother would have taken from what remained of Eren’s stash. Four hours and they came back out to the snow, shivering as they waited for the bus.

She got worse overnight, but insisted that Eren goes to school in her delirious voice. She promised she would be fine. She would still be here when he gets back. Something screamed inside him to stay, to watch her because she has not been eating, but he—

He was so tired. The selfish part of him wanted a few hours at school just so he could stop feeling so helpless and worried and for six hours at school he just wanted to pretend things would be okay. His mother had the flu before. She had gotten better before.

Eren went to school and when he came back only his mother's body was left.

Pneumonia, they told him later, as if it was any use now that she was gone.

If he would have stayed. If he would have insisted that they went to the hospital. If he would have done more—

***

***

***

Levi couldn’t finish reading.

“Eren,” he said, sounding breathless.

Eren wouldn’t meet his eyes. “You didn’t finish reading,” he mumbled, his voice weak.

Levi kept reading, searching for the resolution that he wanted to see. He wanted to see the healing. He wanted to see Eren moving on. But he didn’t see it. Eren was determined to go to med school, he was determined to be of use, he drove himself through hours and hours volunteering at the hospital because he couldn’t stand being useless, of being the helpless boy who abandoned his mother, and no matter how much his adopted family was against it, he wanted to work in a community clinic. Eren wanted to make sacrifices to help people in a system that had failed him.   

Levi gently placed the paper on his desk. “Eren,” he said, but Eren wouldn’t look at him, his eyes glued on to the ground. He placed a hand on Eren’s shoulder, feeling Eren trembling under his touch. “It’s not your fault.”

Eren’s chuckle was bitter. “I could have stayed.”

“Without proper medical attention, she wouldn’t have make it even if you were there,” Levi said.

“I could have done more. I could have called 911.” Eren sounded like a broken record, and Levi wanted to pull Eren into his arms and protect him from the memory that haunted him until now.

“You were ten,” Levi said. “You didn’t know. You believed that she would get better.”

“I never know any better.” Eren’s shoulders shook under his fingers, his voice cracking at the edges. “I—when I volunteered at the hospital, there was this one time that someone—this old woman who came in and she had symptoms so similar to my mom.”

“I kept telling the doctor that it was pneumonia, and he laughed at me, saying it was just a cold. But I—at the moment I was so convinced that it was pneumonia. The doctor at the clinic said it was just a cold too, and I—”

Levi gave up all pretenses of propriety and pulled Eren into his arms.

“I snuck in the antibiotics and I nearly gave her something that she was allergic to.” Eren sobbed into his shoulder. “It wasn’t pneumonia. If I hadn’t doubted myself at the last second I could have killed her—”

“But you didn’t.” Levi rubbed his back. “You doubted yourself. You didn’t let your nightmare took over you completely. You made a different decision.” His shoulder was wet with Eren’s tears, and he swallowed, trying to keep down the grief from Eren that was soaking into his own body. His eyes were stinging, but he blinked back the pain.

“You are going to be a brilliant doctor,” Levi said. “You have seen the other side of the health profession and you’ve lived through the consequences. You know what others do not. And you will be a great doctor because of it.”

Eren clung on to Levi, unable to muffle the sobs that tore through his body. Levi wanted to say that things were going to be okay, but he didn’t. Eren had a better idea of that. So he comforted Eren the only way he knew how—by giving him a shoulder to lean on.  

They broke apart when lunch break came to an end and everyone from lab returned. If anyone saw Eren’s red-rimmed eyes, they didn’t mention it. Some of them gave him a gentle smile and a supportive clasp on the back, and Eren could only manage a weak smile back.

“I’m happy that I came to this lab,” Eren whispered to him. “It’s the only thing that I did without thinking about my mom, and I’m glad I did it. I’m glad that I got to meet you.”

Levi knew Eren was feeling better when he said mockingly. “What? Aren’t you going to say that you’re glad to have met me too?”

“I won’t say that,” Levi scoffed. “But you’re growing on me.” He ruffled Eren’s hair, and Eren batted his hand away, grinning wide.

Eren came by more often since then, and Levi helped him refined his essay to something that the admission board would approve of. They went out to lunch together to discuss the application and sometimes just to talk. A great barrier between them was broken, and Eren began to tell him about other personal things, his friends, his family who took him in when his parents were gone, and his obsession with rock climbing.  

“It sounds fun,” Levi said.

“You want to go together this weekend?”

So that was how Levi was roped into indoor rock climbing. Levi was skeptical at first as Eren showed him how to do pre-climb stretches, and Levi found that he didn’t mind Eren’s hands on him as much as he should. He previewed the route just as Eren said he should, but once he was up on the rock, it was a whole different story.

“You’re too tense!” Eren shouted up at him. “You’re going to wear out your arms. Keep yourself closer to the wall.”

But he wanted to see where he was going, damn it. “I’d like to see you do better,” Levi shouted back.

It turned out that Eren could in fact, do better. He wouldn’t stop laughing at Levi because Levi was stuck on the rock at one point and needed Eren’s directions to get down.

“I’ll master it next time,” Levi promised.

“I’m sure you will,” Eren said. “You actually did a lot better than I did when I first started.”

Despite Eren’s consolation, Levi still wanted to try it again, only to find out that Eren was right. He did wear his arms out badly. At least this time he could get himself down without help.

The only true consolation was the nice view of Eren’s ass as he stretched his body against the wall, and Levi had to stop himself before his thoughts got too weird for public consumption.

They ended up going rock climbing together every weekend, and if they usually went to eat together afterwards, they were clearly going as sort-of friends and not as dates. Probably. Eren was a lot more fun to talk to than he let on, and Levi felt an ease with him that he hadn’t with anyone else.

Levi realized with a wrenching pull in his heart that he really liked Eren. Everything about him. From his past to his determination to his terrible puns to his smiles to his hope for the future. It was hopeless, he knew. Eren was leaving in a month.

Not to mention Levi would violate all the ethics code of being a mentor.

He sank back into his work when Auruo accidentally messed up the laser alignment, and it took him a good month to realign and fool-proof the set up. Auruo apologized profusely, but by then Levi was so relieved that the set up was fine that he didn’t care for the apology. Eren stopped coming into lab completely because he was swarmed with graduation things, and everyone asked Levi how Eren was doing as if he was some sort of source for Eren-related information.

It turned out that he did know the answers to all the questions they were asking him because Eren told him nearly everything that went on with his life. But he was Eren’s mentor, he was supposed to know these things.

Despite both of their busy schedules, they went Christmas shopping together. Fortunately they both disliked shopping, so once they finished buying appropriate gifts within an hour and thirty minutes, they reconvened at the appropriately decorated Christmas tree and decided to go see a movie. It was a science fiction film that had more shootings than it had science, so Levi enjoyed the trashy action film for what it was.

The armrest was wide, but for some reason Eren’s arm was right against his. Levi felt his attention on the film draining by the minute, the heat against his arm scorching to an unbearable degree. He turned to Eren then, only to find that Eren was definitely not watching the movie but was staring at him. Blue light and then orange light flashed across Eren’s face; the heat in Eren’s eyes not unlike the one Levi felt on his skin.

Levi snapped back to the movie, feeling out of breath.

When they left the theater, Eren pretended that nothing happened, and Levi followed suit, not quite sure what he wanted himself.

Levi didn’t have a chance to think about his feelings because he was swept away by Erwin’s suggestions that they do electrical measurements for the sensors. Suddenly Levi had to learn how to be an electrical engineer, and his feelings were set aside for the moment. The project was moving slowly along, but Erwin insisted that it was heading in the right direction, and they both had hopes to get funding from the NIH.

“I highly doubt it though,” Levi sighed, and Eren patted his shoulder comfortingly.

“You don’t need the NIH,” Eren said.

“Yeah, but it would be nice not to scrape by.” Levi said. “Alright, enough about me. What have you been up to lately?” He let Eren’s ranting on the moving situation to distract him from the NIH let down.

Before Levi knew it, December came, and with it came Eren’s graduation. Eren managed to procure a ticket for him even though all the graduates were fighting tooth and nail for any extra tickets.

“You know, you could probably sell this ticket for three times the original price. Make a profit,” Levi said to hide the emotion bubbling up his throat as Eren handed him the ticket. He didn’t think he was someone important enough for Eren to want at graduation.

“I need you to be there,” Eren said shyly, and Levi’s breath hitched.

“You better graduate with honors,” Levi mumbled to distract himself from his feelings.

“Highest honors, actually,” Eren grinned. “My roommate who’s in the same spectroscopy class with me this summer was in the running for highest honors too, but I had an advantage.”

“What’s the advantage?”  

“You.”

Levi looked away, feeling too warm and tingly inside. “Don’t expect any reward from me then.”

“Just you being there at graduation is enough,” Eren said, ears turning pink. It was really unfair, Levi thought, how Eren could utterly crushed him so easily with his earnest words. Eren should stop. Levi didn’t know how much feelings he could repress before he burst like a cell under low solute conditions.

It wasn’t a reward, but Levi bought a gift for Eren already, back when they went Christmas shopping together. It was in a simple silver box with a blue bow on top because Levi didn’t know how to wrap gifts, but Eren beamed when Levi gave it to him on graduation day like it was the best gift that he could ever receive. Levi sighed in relief even though he told himself repeatedly the day before that he didn’t care just so he wouldn’t wimp out on giving Eren the gift.

Eren looked very fetching in the terrible oversized black graduation gown that the university made him wear, aided by the numerous cords and the gold ‘Highest Honors’ sash. Eren’s uncle clasped hands with Levi and ushered him in the family picture with all of them, and despite his protest, he was squished under Eren’s arms and Eren’s aunt to his side as they all but screamed “Congrats to Eren” when his uncle snapped the picture.

The relatives then shuffled Eren back and forth for more pictures, and by the time he returned to Levi’s side, he was out of breath but so elated that Levi felt the same happiness reflected on to him.

“Before we were interrupted,” Eren said. “I was going to see what terrible gift you have inflicted on me.”

“Open it,” Levi grinned.

Eren did. He quirked his eyebrow at Levi when he saw a simple mug nestled inside the box, but his face broke into a delighted expression when he pulled it out and saw the picture on the mug.

“A pun,” Eren said incredulously. “I can’t believe you got me a pun as a graduation present.”

“It’s a fair payback,” Levi laughed as Eren tackled him into a hug to the amusement of Eren’s family. Levi felt his face burned even as Eren pulled away reluctantly.

The mug had an artistic rendition of a DNA strand with the printed words, “Coded for success.” Levi felt that it was a fitting mug for Eren, and as he watched Eren standing tall and proud with his accomplishments, as he thought about what Eren had been through and how he got here now, he felt himself being overcome with emotions.

“Eren,” Levi said. “All the successes that are here with you today, it’s all you. You stood up despite the pain and failure of the past—” Here, he paused.

“No, that’s not right is it? You stood up because of them, and you have become stronger because of it. I’m proud of you, and all your family and friends are proud of you. I’m glad that I’ve gotten a chance to meet you because you’re truly an inspiration.”

Eren swallowed, his eyes glossy and wet. “Do you think my mom would have been proud?” He asked softly.

“Of you? Any parent would be,” Levi said.

Eren pulled him in to his arms again, and Levi closed his eyes, lending Eren his shoulder one last time as he let go of the remaining tears. As Eren pulled away, Levi saw that he stood taller, more confident and sure of himself now, and Levi’s pride for him swelled.

“You know, I could kiss you right now,” Eren grinned.

Something clicked in Levi’s brain then. Without a warning, he grabbed Eren by the front of his gown and pulled him down into a kiss. Levi could hear gasping from Eren’s family, but he didn’t care because Eren’s lips were warm and soft against his, and when they broke away, Eren had the most stunning blush on his cheeks.

“What was that for?” Eren said. He didn’t look like he minded it.

 “Just something for you to remember me by,” Levi said as he fixed Eren’s tie and smoothed down the front of his gown. “Remember to keep in touch.”

“I don’t think I can forget you if I try,” Eren mumbled before capturing Levi’s lips for another kiss.

A camera flashed next to them, and Levi felt, in that moment, like he had won all the Nobel Prizes in the world.

**Author's Note:**

> References:
> 
> 1) Gong, Y. et al. Imaging neural spiking in brain tissue using FRET-opsin protein voltage sensors. _Nat. Commun_. 5:3674 (2014).
> 
> 2) Gel Electrophoresis. (http://en.wikipedia.org/wiki/Gel_electrophoresis)
> 
> 3) Förster resonance energy transfer: FRET. (http://en.wikipedia.org/wiki/F%C3%B6rster_resonance_energy_transfer)
> 
> 4) Mass Spectra, the M + 2 peak. (http://www.chemguide.co.uk/analysis/masspec/mplus2.html#top)
> 
> 5) The Chemistry of Beer Brewing. (http://www.esu.edu/~scady/mueller/home.htm)
> 
> Abbreviations:
> 
> 1) NIH: National Institute of Health
> 
> 2) ALS: Advance Light Source
> 
> 3) SEM: Scanning Electron Microscope.


End file.
